ii8 AMERICAN PERMIAN VERTEBRATES 



the splenials. The coronoid is rather low, rounded, and thin. 

 Reaching as far back as the teeth is the large opening of the inner 

 side. The articular was free on one side; it is a small bone, with- 

 out an anterior or pre-articular process, concave on the upper 

 surface for the quadrate. There is no post-articular process. 

 The sutural surface for the union of the articular bone is nearly 

 vertical, and shows a distinct suture running through the middle 

 between the angular and surangular bones, both of which reach 

 quite to the hind end of the mandible. Below and in front, the 

 pre-articular borders the lower margin, as usual, of the internal 

 vacuity. 



Teeth. — The teeth of Casea are very characteristic, unlike any 

 that have hitherto been made known from the American Permian. 

 There were eleven on each side above and below: two on each 

 premaxilla, nine on each maxilla, and eleven in each dentary. 

 The anterior six of each jaw are materially larger than the posterior 

 five, the last of which are very small. The two premaxillary 

 teeth and the first four of the maxilla and front six of the mandibles 

 are very stout, conical, nearly circular at their base, but more 

 rounded at the apex, and perhaps a little flattened from within 

 outward. They are somewhat pleurodont in their attachment, 

 but probably have roots firmly inserted in the bone. Those of 

 the upper jaws are vertical in position, while the first six or more 

 of the mandible are more or less prognathous, the anterior ones 

 directed outward and forward at an angle of forty degrees or more. 

 None of the teeth have a sharp apex, and the rows are almost 

 continuous, the base of the crowns almost touching. The teeth 

 are evidently phytophagous. 



Presacral vertebrae. — The presacral series comprises twenty- 

 four, all found in close articulation .with skull and sacrum and a 

 considerable part of the tail in specimen No. 657. The vertebrae 

 shown in Plate XV are the connected series of specimen No. 655, 

 from the eighth to the sacrum, with a disconnected third vertebra. 

 The first seven figured in Plate XIV are of specimen No. 657. 

 The vertebrae of No. 655 had been prepared and drawn in the 

 confident expectation that the series would be found to be com- 

 plete, an expectation, however, which resulted in disappointment. 



